Methods and apparatuses for joining a pumping cartridge to a pump drive

ABSTRACT

Apparatus and methods of their use are described for engaging a pumping cartridge with a pump drive. In certain embodiments, the cartridge, comprising a cylinder and a movable piston assembly, is initially assembled or subsequently positioned so that the distance between the attachment point on the piston assembly for coupling to a drive assembly, and a reference point on the cylinder, is greater than the maximal distance that will be encountered during normal oscillation of the piston during use. The cartridge, in certain embodiments may be pressed into a drive assembly having means for immobilizing the cartridge and means for coupling the piston assembly to the driveshaft. In certain embodiments, when the cartridge is fully inserted into the drive assembly, the piston is pressed into the cylinder sufficiently to establish a selected distance so that the piston shaft is in the proper position to engage with a coupling mechanism carried on the driveshaft.

RELATED APPLICATION

This non-provisional application claims the benefit under Title, U.S.C.§119(e) of co-pending U.S. Provisional Application Ser. No. 60/440,123,filed Jan. 15, 2003, which is incorporated herein by reference. Thisapplication is a continuation-in-part of U.S. Application Ser. No.10/754,905, filed Jan. 9, 2004 now pending; which is a continuation ofU.S. Application Ser. No. 10/134,970, filed Apr. 29, 2002, nowabandoned; which claims priority U.S. Provisional Application Ser. No.60/287,219, filed Apr. 27, 2001, each of which is incorporated herein byreference.

BACKGROUND

1. Field of the Invention

The invention relates generally to pumping systems employing pumpingcartridges that can be disengaged from a pump drive unit, and, morespecifically to methods of joining a pumping cartridge to a pump drivein such pumping systems and interconnect mechanisms facilitating suchmethods.

2. Description of the Related Art

A piston pump typically includes several cooperating elements. Thesetypically include at least a cylinder, a piston moving in the cylinder,and a drive shaft connected to the piston that moves the piston back andforth in the cylinder. Other elements typically include one or morecheck valves, or functional equivalents, so that fluid is drawn in froma source and expelled into an outlet. Normally, the drive shaft ispermanently fastened to a mechanism providing the reciprocal motion.

In certain medical applications, it may be desirable to providedisposable pump elements that contact fluids being pumped, e.g.disposable piston pumping cartridges, for example to preventtransmission of disease between patients. For the sake of economy, itmay be advantageous for the mechanism providing reciprocating force tobe separate from the pumping elements. The disposable portion of apiston pump, typically comprising a cylinder, a piston, and valves, canadvantageously be fabricated as a separate cartridge. The cartridge can,for certain applications, be provided in a sterile condition, so thatthe fluid pumped will not be contaminated. Such a cartridge can beconfigured to be reversibly attached to a reusable drive mechanism,typically comprising a motor, which reciprocates the piston via, forexample, a reversible linkage.

In one mode of medical use, such as described in certain of theApplicant's commonly owned patents and patent applications (e.g. U.S.Pat. Nos. 6,216,573; 5,944,686; 6,375,635; 6,511,493; and U.S. Pat.Application Pub. No. 2002/0176788-A1, each incorporated herein byreference), such a disposable cartridge can used to generate a highpressure, such as 5,000 p.s.i, 10,000 p.s.i, or 20,000 p.s.i or more.The resulting high pressure water jet can be used, for example, to cutand/or remove and/or clean tissue, or to drive rotary tissue-abradingelements. In one mode of making such cartridges, described in moredetail in commonly-owned US 2002/0176788-A1, the piston is provided withan abradable flange as a sealing element. Such disposable cartridgesmay, in certain embodiments, be designed to be used only for a singlemedical procedure, and thus may require relatively frequent replacement.

In a medical environment, such as an operating room, there are severalconstraints that may be desirable to be satisfied in a procedure forcoupling a piston to a drive that make such a procedure technicallychallenging. First, it may be desirable that the connection can be madewithout removing the piston from the cylinder, since that would tend torender the pumping zone non-sterile. Second, may be desirable for it tobe possible for the operator to be able to replace the pump while theoperator is wearing gloves, and without contaminating the operator (whowill typically be a physician or a nurse.) Third, it may be desirablethat the connection method can enable the disposable components to becoupled to the resuable components reliably on the first try and withoutextensive operator training or difficulity. In addition, it may bedesirable that the connection mechanism be able to be fabricatedeconomically so as to add as little expense to the overall disposablecartridge as possible.

SUMMARY

Apparatuses and methods for connecting a disposable pumping cartridge toa pump drive that can, in certain embodiments, meet one, more, or all ofthe above requirements are described. In an exemplary embodiment, amethod and system of coupling is described that comprises “parking” apiston in a portion of a cylinder that is other than its normaloperating zone, and that is positioned farther from a high pressurefluid-containing end of the cartridge than the operating zone. This“Parking” procedure can be used to position a piston in a cylinder sothan when the cartridge is inserted into a drive, the piston can,optionally without further intervention, be positioned so that aprovided coupling mechanism can, in some cases reliably and simply,couple the piston to the drive mechanism.

Apparatus and methods of their use are described for engaging a pumpingcartridge with a pump drive. In certain embodiments, the cartridge,comprising a cylinder and a movable piston assembly, is initiallyassembled or subsequently positioned so that the distance between theattachment point on the piston assembly for coupling to a driveassembly, and a reference point on the cylinder, is greater than themaximal distance that will be encountered during normal oscillation ofthe piston during use. The cartridge, in certain embodiments may bepressed into a drive assembly having means for immobilizing thecartridge and means for coupling the piston assembly to the driveshaft.In certain embodiments, when the cartridge is fully inserted into thedrive assembly, the piston is pressed into the cylinder sufficiently toestablish a selected distance so that the piston shaft is in the properposition to engage with a coupling mechanism carried on the driveshaft.

In a first series of embodiments, a method for reversibly coupling apumping cartridge to a reusable pump drive system is described. Themethod comprises: providing the reusable pump drive system with a firstpumping cartridge retaining component configured and positioned toenable it to engage a first portion of the cartridge, the first pumpingcartridge retaining component being adjustable between a retainingposition and a non-retaining position; providing a driveshaft of thereusable pump drive system with a second pumping cartridge retainingcomponent configured and positioned to enable it to engage a secondportion of the cartridge comprising a portion of a piston shaft of thepumping cartridge, the second pumping cartridge retaining componentbeing adjustable between a retaining position and a non-retainingposition; preparing the pumping cartridge for connection to the reusablepump drive system by placing a piston of the pumping cartridge in aselected position relative to a cylinder of the pumping cartridge;inserting the pumping cartridge into the reusable pump drive system;adjusting the first and second pumping cartridge retaining components totheir non-retaining positions; and moving at least one of the first andsecond pumping cartridge retaining components to its retaining position.

In certain such embodiments, the selected position is chosen so that thefirst portion of the cartridge and the second portion of the cartridgeare separated by a distance enabling both the first and second pumpingcartridge retaining components to be positioned in their retainingpositions. The selected position can then be obtained by the steps of:moving the piston relative to the cylinder so that a distance separatingthe first portion of the pumping cartridge and the second portion of thepumping cartridge comprising a portion of the piston shaft is greaterthat an engaging distance separating the first portion of the pumpingcartridge and the second portion of the pumping cartridge comprising aportion of the piston shaft; and inserting the pumping cartridge intothe pump drive system so that during insertion of the cartridge into thepump drive system the piston is moved into the selected position,wherein the distance separating the first portion of the pumpingcartridge and the second portion of the pumping cartridge comprises theengaging distance.

In certain embodiments of the first series of embodiments, the selectedposition is indicated by a detectable position indicator, while in theseor other embodiments, after the moving step, a step of using the pumpingcartridge in a medical pumping procedure is performed. In certain ofthese or other embodiments, the pumping cartridge is constructed andarranged to enable it to withstand and generates a pressure of at leastabout 5,000 p.s.i., without failure or leakage.

In certain embodiments of the first series of embodiments, the selecteddistance is obtained by engaging the first portion of the pumpingcartridge with the first pumping cartridge retaining component; movingthe driveshaft of the pump drive system to a first end of its range,wherein the driveshaft is in its distal-most position in which adistance between a distal end of the driveshaft and the cylinder is assmall as possible; and then engaging the second pumping cartridgeretaining component with the second portion of the pumping cartridgecomprising the portion of the piston shaft.

In another series of embodiments, a method for reversibly coupling apumping cartridge to a driveshaft of a reusable pump drive system isdisclosed. The method comprises: providing the reusable pump drivesystem with a first pumping cartridge retaining component configured andpositioned to enable it to engage a first portion of the cartridge, thefirst pumping cartridge retaining component being adjustable between aretaining position and a non-retaining position; providing a driveshaftof the reusable pump drive system with a second pumping cartridgeretaining component configured and positioned to enable it to engage asecond portion of the cartridge comprising a portion of a piston shaftof the pumping cartridge, the second pumping cartridge retainingcomponent being adjustable between a retaining position and anon-retaining position; inserting the pumping cartridge into the pumpdrive system; adjusting the first pumping cartridge retaining componentto the retaining position; moving the driveshaft of the pump drivesystem to a first end of its range, wherein the driveshaft is in itsdistal-most position in which a distance between a distal end of thedriveshaft and the cylinder is as small as possible; and engaging saidsecond pumping cartridge retaining component with the second portion ofthe cartridge comprising a portion of the piston shaft of the pumpingcartridge, so as to couple the piston shaft to the driveshaft.

In yet another series of embodiments, a method for coupling apresterilized pumping cartridge to a reusable pump drive assembly isdisclosed. The method comprises: positioning a piston assembly portionof the pumping cartridge in a first position within the cylinder, thefirst position being proximal to an operating region of the cylinder inwhich a piston reciprocates during operation; sterilizing at least acylinder assembly portion of the pumping cartridge; inserting thecartridge sterilized in the sterilizing step into the pump driveassembly; engaging a first retaining component of the pump driveassembly with a first portion of the cartridge; and engaging a secondretaining component of a driveshaft of the pump drive assembly with thepiston assembly portion of the cartridge. In certain embodiments of themethod, before sterilizing the cartridge, a step of sealing the pumpingcartridge in sterilizable packaging can be performed. In certain ofthese or other embodiments, the cartridge may be removed from thesterilizable packaging after sterilization.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are schematic are not intended to be drawn toscale. In the figures, each identical, or substantially similarcomponent that is illustrated in various figures is typicallyrepresented by a single numeral or notation. For purposes of clarity,not every component is labeled in every figure, nor is every componentof each embodiment of the invention shown where illustration is notnecessary to allow those of ordinary skill in the art to understand theinvention. In the drawings:

FIG. 1 is a schematic cross-sectional illustration of portions of apumping cartridge assembly according to one embodiment of the invention;

FIG. 2 is a schematic cross-sectional illustration of portions of acartridge inserted into an adaptor on a drive shaft that connects to apump drive (not illustrated), according to one embodiment of theinvention;

FIG. 2A is a schematic illustration of one embodiment of a piston shaftengaging member of the pump drive shaft of FIG. 2;

FIG. 3 is a schematic cross-sectional illustration of portions of apumping cartridge assembly and an adaptor on a drive shaft that connectsto a pump drive (not illustrated) illustrating certain dimensional andpositional relationships among the components, according to certainembodiments of the invention; and

FIG. 4 is a schematic cross-sectional illustration of portions of apumping cartridge assembly and an adaptor on a drive shaft that connectsto a pump drive (not illustrated) illustrating certain dimensional andpositional relationships among the components, according to certainembodiments of the invention.

DETAILED DESCRIPTION

To more clearly illustrate certain aspects of the invention, aparticular, exemplary embodiment is described below. Numerous variationsare possible that encompass the same invention, and the invention islimited only by the claims appended hereto, and is not limited to theexemplary configurations and dimensions set forth in this detaileddescription.

FIG. 1 is a schematic illustration showing a pumping cartridge assembly,according to an embodiment of the invention, generally labeled 1. Thecartridge, in this embodiment, has two parts, a piston assembly 10 and acylinder assembly 30. The piston assembly 10 has a connecting region 12and a body region 28. The connecting region 12 comprises a terminal knob14, a groove 16, and a shaft 18 meeting body 20 at lip 19. Body region28 has a body 20, a fluid inlet 21 connecting with a check valve 24 (thestructure of which is described in greater detail in US2002/0176788-A1); and a piston 22 carried on body 20 and having asealing flange 26 (the structure of which is described in greater detailin US 2002/0176788-A1). The flange 26, in certain embodiments, protrudesslightly beyond the diameter of the body 20 and the piston 22 to providea seal against the cylinder wall. The flange 26 may be designed to beerodible in use. The check valve 24 may be oriented so that fluid canmove into inlet 21 and out of the check valve, but cannot flow back intothe check valve when the piston compresses the fluid. In other words,the check calve 24 may be arranged so that fluid flows to the right(“distally”) in the cartridge as illustrated.

The other portion of the cartridge of the particular embodimentillustrated is the cylinder assembly 30. The cylinder assembly 30comprises a wall 32 surrounding a cavity 34. The cavity may be slightlybroader at a proximal portion 36 forming a piston storage region toaccommodate the flange 26 when the piston is not in use. This “parked”position can prevent or reduce irreversible deformation of the flange 26during storage, and is also useful for positioning of the piston, asdescribed below. A second check valve is positioned at 38, likewiseoriented so that fluid flows only to the right (distally). An outletfitting 40 carries a barb or other hose connection 42, and a positioningnotch 44. In normal operation, the piston reciprocates in a defined zone46, which is distal of the “parking” zone (i.e. piston storage region)demarcated by relief 36.

Many other detailed constructions of a cartridge are possible; severalare illustrated and/or described in US 2002-0176788-A1. As will be seenbelow, some features of a cartridge that may be advantageous for use incertain embodiments of the invention are the existence of positioningelements on each of the piston assembly and the cylinder that compriseor are functionally equivalent or similar to groove 16 and notch 44. Asecond feature, provided in some embodiments, is the ability of thepiston assembly to remain assembled in the cartridge while outside of(proximal to) its normal operating zone, i.e., to be parked or stored.

FIG. 2 is a schematic illustration of a cartridge inserted into anadaptor 60 on a drive shaft that connects to a pump drive mechanism (notillustrated). The drive mechanism will typically will comprise a motorwith appropriate controls, gearing, etc., and will be configured tocause the drive shaft adaptor 60 to reciprocate in the proximal/distaldirection. Drive shaft adaptor 60 has a cavity 62, which may be slightlylarger in diameter than piston shaft 18, and a back end at 68 and afront end at 70. Drive shaft adaptor 60 also may have one or more pistonshaft retaining components, such as one or more movable pins (orfunctional equivalent) 64. Pins 64 may have a rounded inner end 66designed to facilitate engagement with and to fit into groove 16 on thepiston shaft 18. When pin 64 is lowered and groove 16 is below pin 64 sothat the lower end 66 of the pin is in the groove, then the pistonassembly 10 is locked to drive shaft adaptor 60 and can reciprocate withit.

When pin 64 is raised, piston shaft 18 can be withdrawn from cavity 62and removed from the adaptor 60. Apparatus for raising and lowering pins64 or equivalent is not illustrated, and may take many forms, as wouldbe apparent to those skilled in the art. In one embodiment, FIG. 2A, apair of pins 64 connected to a ring 65, which can be looped around anelongated raising member (not shown), and slide freely along the raisingmember when the drive shaft reciprocates. When the driving mechanism isturned off and the raising member is raised, the pins are liftedsufficiently to allow removal or inserting of a piston shaft 18. Withsuch a design, removal is possible at any point in the stroke of thedriveshaft. The pins could be replaced with a blade, or prongs, or otherdevices, and moved to engage the shaft, and removed to disengage theshaft, from any direction, including from below, or from the side, orfrom more than one direction, as would be apparent to those skilled inthe art. Insertion of the pair of pins 64 can be by gravity, but in someembodiments there is a bottom segment to the loop so that the raisingmember can also push the pins downward so as to engage groove 16 (seeFIG. 2A.)

Referring again to FIG. 2, a block 80 has a cylindrical passage 82through it that may be slightly larger in diameter than cylinder outerwall 32. Associated with block 80 is a pump cartridge cylinder retainingcomponent 84 with an inner end 86 that is sized and positionable to fitinto notch 44 of the cylinder assembly. Retainer 84 is shown in a closedconfiguration in which it retains the cylinder assembly 30 in thepassage 82, and retainer 84 may be configured so that it can be raisedto release the cartridge, or to allow insertion of the cartridge. Theraising mechanism can take any of a variety of forms, as would beapparent to those skilled in the art, and is not illustrated.Optionally, the raising mechanism for retainer 84 may be coupled to theraising mechanism for pin 64, in embodiments which allow thesimultaneous operation of the two latching mechanisms.

Driveshaft adaptor 60 operates within a drive assembly (not illustrated)in which the position of block 80 is fixed. (Other components of thedrive assembly can typically include the housing and the motor and itscontrols, which are typically fixed in relation to block 80). The pumpdrive assembly (which may also be called a console, or similar terms) istypically covered with a housing preventing operator contact with movingparts and electrical or electronic components, etc. Pin 64 may beconnected to a lifting and lowering mechanism, which in one embodiment,as described above, is constructed so that pin 64 can reciprocate alongwith driveshaft adaptor 60, and still be raised when removal of theremovable pumping cartridge from the pump drive assembly is desired.Optionally, the pump drive assembly may be constructed, for example byprovision of mechanical or electronic interlocks, so that neither pin 64nor retainer 84 can be raised while driveshaft 60 is in motion.

The exemplary configuration illustrated in FIG. 2 demonstrates one ofthe problems that could occur when inserting a cartridge into the driveassembly, and embodies one inventive solution, as described below. Ifdriveshaft adaptor 60 is in its most proximal (to the left asillustrated) position, and/or piston assembly 10 is in its most distalposition, then pin 64 may not be able to become engaged with groove 16,even when the cartridge is fully inserted so that notch 44 can beengaged by retainer 84, unless the components are configured, accordingto the invention, such that certain relative dimensions of the cartridgeand driveshaft adaptor are provided, according to the invention, asdescribed below.

FIG. 3 presents one set of controlled dimensions according to certainembodiments of the invention. The front and back ends of the cartridgeare shown, as well as proximal 61 and distal 63 positions of thedriveshaft adaptor 60, the groove 16 and the piston 22. Distance (a) isthe distance separating proximal engaging pin 64 and distal engaging pin84 on the reusable pump drive assembly, when driveshaft adaptor is inits most distal position at the end of a discharge stroke. Distance (b)is the distance separating proximal engaging pin 64 and distal engagingpin 84 on the reusable pump drive assembly, when driveshaft adaptor isin its most proximal position at the start of a discharg stroke.Distances (a) and (b) should be selected so that they correspond to thedistances between groove 16 and groove 44 of the pumping cartridge, whenthe piston is in the fully distal position and fully proximal positions,respectively, in the normal operating zone of cylinder 32. The distance(c), representing the difference between (a) and (b) should thus beabout the same as the travel distance of the piston and of thedriveshaft during a pump stroke. Accordingly, it may be advantageous forcartridges and drive assemblies to be constructed to a common standardof dimensions (a) and (b) so as to be more effectively usable together.

Referring now to FIG. 4, the distance (d) between pin 64 and the frontedge 70 of the driveshaft adaptor 60 may be essentially the same as thedistance between the groove 16 and the lip 19 of the piston assembly 10.Alternatively, the distance between the groove 16 and the lip 19 of thepiston assembly 10 could be somewhat longer than distance (d), or thelip 19 may not be present at all, in some embodiments. In these or otherembodiments, the distance (e) between the pin 64 and the back of thedriveshaft cavity 68 may be essentially the same as the distance betweenthe groove 16 and the proximal end of the knob 14 (or functionalequivalent).

Taking into account the above-discussed dimensional relationships, it ispossible to arrange the reusable drive assembly and pumping cartridgeconfigurations to facilitate reliable insertion of a pumping cartridgeinto a drive assembly so that the piston groove is properly positionedto be engaged by pin 64, or functional equivalent, once the cartridge isinserted into the block 80 or equivalent and positioned so that retainer84 or equivalent can be engaged. In a first method of assembly, thepiston assembly 10 is initially positioned proximally of the operatingzone 46, i.e., “parked” proximally of the operating region (see FIG. 1).In the design shown in FIG. 1, this is the proximal end 48 of cavity 34.This region can optionally be machined to have a flange relief zone 36,in which the flange 26 on piston 22 is not compressed. Then, the pistoncan be positioned in this zone during manufacture, sterilization, and/orshipping, so that the sterilized cartridge is delivered to a customerready to be inserted into the drive assembly without furthermanipulation. When the piston is pre-positioned in this way, the act ofpushing the pumping cartridge into the drive assembly until it stopstends to facilitate the correct positioning of the lip 19 or of the knob18 to allow for the engagement of the driveshaft adaptor 60 andengagement of pin 64 into groove 16, thereby reversibly connecting thepiston assembly with the driveshaft.

In an alternative embodiment, the initial position of the piston can beirrelevant if certain control features are added to the drive assembly.In this embodiment, the cartridge is first inserted into block 80 and,optionally, retainer 84 is engaged. Then the driveshaft adaptor 60 ismoved to its extreme distal position, under manual or electroniccontrol. With proper dimensioning, as discussed above, this can ensurethat groove 16 is positioned so that it can be engaged by pin 64,thereby connecting the piston assembly to the driveshaft adaptor. As anoption, proper connection could be detected, for example by sensing thedepth to which pin 64 penetrates into chamber 62 when engagement isattempted. Such an embodiment could also be supplemented by adding acontrolling element that would position the driveshaft adaptor 60 at itsmost forward (distal) position upon shutdown of the drive assembly, orat its startup. This embodiment is also compatible with a pre-parkedpiston assembly version of the pumping cartridge, discussed above.

Useful additional features can be provided in certain embodiments. Oneoptional feature is the provision of means for selectively controllingwhich of a variety of pumping cartridge types can be used with aparticular drive assembly. For example, a cartridge of a first typerequiring a higher pressure than other types of cartridges might beconfigured to not fit into or otherwise be unusable in an older driveassembly that cannot drive a cartridge to the required pressure. In oneembodiment, the selective control means could comprise projectionsattached to outlet element 30 (see FIG. 1), or to other elementsremaining outside of the drive assembly, that would prevent fullinsertion of the cartridge into the block 80 unless the drive and/orblock had a mating feature, into which the pins could slide. In anotherembodiment, the cartridge and the drive assembly could containelectronic elements so that one could read the other's configuration,and would send signals to the operator, or to a system controller in theconsole, indicating a mismatch, and optionally interrupting the startingprocess of the drive assembly.

In the exemplary embodiment described above, the engaging mechanismbetween the reusable pump drive assembly and the pumping cartridgepiston has been described as a pair of pins 64. The pins slide into thegroove 16 on opposite sides of the piston shaft, as if the pins were aminiature tuning fork. In certain embodiments, the dimensions (e) and(d) (see FIG. 4) are selected such that the high force applied to thepiston shaft in the compression stroke can be absorbed by lip 19 and/orknob 14 so that the pins 64 are not subject to high shearing forces. Insuch embodiments, the pins may only need to be configured withsufficient strength to enable them to withstand and transmit to thepiston shaft, the lower force needed to slide the piston proximally onthe return stroke. However, any of a variety of other latchingmechanisms could provide the same or equivalent effect. As noted above,mechanical equivalents comprise any means of placing an engaging memberso that it intrudes into groove 16, so that the piston is pulledbackward during the return stroke.

The engaging/latching mechanism for engaging the piston shaft does notneed to be locatable/movable inside of cavity 62, but could also, oralternatively, be mounted on forward face 70 of driveshaft adaptor 60 toengage a groove or other feature of the piston shaft. For example, in anembodiment where a groove is provided just proximally of lip 19, thepiston shaft could be engaged there by a suitably positioned engagingmechanism.

Another embodiment for achieving operable engagement between the pistonshaft and cavity 62 of the drive adaptor 60 involves providing aconfiguration allowing the closing of (i.e reduction in diameter of)driveshaft cavity 62 upon piston shaft 18. For example, the driveshaftadaptor 60 could have a longitudinal cut through its cross-sectionextending distally through forward face 70 and could be squeezed shut bya collet, clamp, etc. Or, in another embodiment, a collet element couldbe rotated to induce grasping of piston shaft 18. In anotheralternative, the groove 16 in piston shaft 18 could be replaced by aslot or a hole in or through piston shaft 18. This alternative couldrequire providing a means for controlling the rotational orientation ofpiston shaft 18 within cavity 60.

Removable/disposable pumping cartridge configurations that can be used,or can be modified, for example as described below, to be usable, in thecontext of the present invention are described in US 2002-0176788-A1,along with information regarding materials of construction of thevarious components and methods of fabrication. Many such cartridges aresuitable for use in the pressure range of 20,000 p.s.i or more. Fordesigns for use at such high operating pressures, operating withrelatively short piston stroke lengths and at high reciprocationfrequency can be advantageous. The following recites certain exemplaryranges of dimensions that may be advantageously employed in practicingcertain embodiments of the invention in which pumping cartridges areintended to be operated at pressures in the 5,000-20,000+ p.s.i.pressure range. In such embodiments, piston shaft 20 may have a diameterof between about 7 to 13 mm. The stroke length (distance (c) in FIG. 3)may be in the range of between about 3 to 12 mm., depending both on thedesired volume delivery rate and on drive speed. The shortest distancefrom notch 44 to groove 16, i.e., distance (a) in FIG. 3, may be in therange of between about 6 to 9 cm. When a “parking region” for the pistonis present in the pumping cartridge cylinder, its length may be similarto the stroke length, but somewhat larger than the length of the piston22, for example in the range of between about 5 to 15 mm.

As disclosed in US 2002-0176788-A1, in certain embodiments, at leastsome of the conventional roles of pistons and cylinders can be reversed,so that, for example, a piston can be held stationary while a cylinderassembly is moved back and forth. Likewise, a sealing element, analogousto flange 23 of piston 22 (see FIG. 3) may be positioned on a piston (asillustrated in FIG. 3), and/or on the wall of a cylinder. Suchvariations are considered to be included within the scope of theinvention.

While several embodiments of the invention have been described andillustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and structures for performing thefunctions and/or obtaining the results or advantages described herein,and each of such variations, modifications and improvements is deemed tobe within the scope of the present invention. More generally, thoseskilled in the art would readily appreciate that all parameters,dimensions, materials, and configurations described herein are meant tobe exemplary and that actual parameters, dimensions, materials, andconfigurations will depend upon specific applications for which theteachings of the present invention are used. Those skilled in the artwill recognize, or be able to ascertain using no more than routineexperimentation, many equivalents to the specific embodiments of theinvention described herein. It is, therefore, to be understood that theforegoing embodiments are presented by way of example only and that,within the scope of the appended claims and equivalents thereto, theinvention may be practiced otherwise than as specifically described. Thepresent invention is directed to each individual feature, system,material and/or method described herein. In addition, any combination oftwo or more such features, systems, materials and/or methods, providedthat such features, systems, materials and/or methods are not mutuallyinconsistent, is included within the scope of the present invention. Inthe claims (as well as in the specification above), all transitionalphrases or phrases of inclusion, such as “comprising,” “including,”“carrying,” “having,” “containing,” “composed of,” “made of,” “formedof,” “involving,” and the like shall be interpreted to be open-ended,i.e. to mean “including but not limited to” and, therefore, encompassingthe items listed thereafter and equivalents thereof as well asadditional items. Only the transitional phrases or phrases of inclusion“consisting of” and “consisting essentially of” are to be interpreted asclosed or semi-closed phrases, respectively. In cases where the presentspecification and a document incorporated by reference includeconflicting disclosure, the present specification shall control.

1. A method for reversibly coupling a pumping cartridge to a reusablepump drive system, the method comprising: providing the reusable pumpdrive system with a first pumping cartridge retaining componentconfigured and positioned to enable it to engage a first portion of thecartridge, the first pumping cartridge retaining component beingadjustable between a retaining position and a non-retaining position;providing a driveshaft of the reusable pump drive system with a secondpumping cartridge retaining component configured and positioned toenable it to engage a second portion of the cartridge comprising aportion of a piston shaft of the pumping cartridge, the second pumpingcartridge retaining component being adjustable between a retainingposition and a non-retaining position; preparing the pumping cartridgefor connection to the reusable pump drive system by placing a piston ofthe pumping cartridge in a selected position relative to a cylinder ofthe pumping cartridge; inserting the pumping cartridge into the reusablepump drive system; adjusting the first and second pumping cartridgeretaining components to their non-retaining positions; and moving atleast one of the first and second pumping cartridge retaining componentsto its retaining position.
 2. The method of claim 1, wherein theselected position is chosen so that the first portion of the cartridgeand the second portion of the cartridge are separated by a distanceenabling both the first and second pumping cartridge retainingcomponents to be positioned in their retaining positions.
 3. The methodof claim 2 wherein the selected position is obtained by the steps of:moving the piston relative to the cylinder so that a distance separatingthe first portion of the pumping cartridge and the second portion of thepumping cartridge comprising a portion of the piston shaft is greaterthat an engaging distance separating the first portion of the pumpingcartridge and the second portion of the pumping cartridge comprising aportion of the piston shaft; and inserting the pumping cartridge intothe pump drive system so that during insertion of the cartridge into thepump drive system the piston is moved into the selected position,wherein the distance separating the first portion of the pumpingcartridge and the second portion of the pumping cartridge comprises theengaging distance.
 4. The method of claim 1, wherein the selectedposition is indicated by a detectable position indicator.
 5. The methodof claim 1, further comprising after the moving step, the step of: usingthe pumping cartridge in a medical pumping procedure.
 6. The method ofclaim 1, wherein the selected distance is obtained by engaging the firstportion of the pumping cartridge with the first pumping cartridgeretaining component; moving the driveshaft of the pump drive system to afirst end of its range, wherein the driveshaft is in its distal-mostposition in which a distance between a distal end of the driveshaft andthe cylinder is as small as possible; and then engaging the secondpumping cartridge retaining component with the second portion of thepumping cartridge comprising the portion of the piston shaft.
 7. Themethod of claim 1, wherein the pumping cartridge is constructed andarranged to enable it to withstand and generates a pressure of at leastabout 5,000 p.s.i., without failure or leakage.
 8. A method forreversibly coupling a pumping cartridge to a driveshaft of a reusablepump drive system, the method comprising: providing the reusable pumpdrive system with a first pumping cartridge retaining componentconfigured and positioned to enable it to engage a first portion of thecartridge, the first pumping cartridge retaining component beingadjustable between a retaining position and a non-retaining position;providing a driveshaft of the reusable pump drive system with a secondpumping cartridge retaining component configured and positioned toenable it to engage a second portion of the cartridge comprising aportion of a piston shaft of the pumping cartridge, the second pumpingcartridge retaining component being adjustable between a retainingposition and a non-retaining position; inserting the pumping cartridgeinto the pump drive system; adjusting the first pumping cartridgeretaining component to the retaining position; moving the driveshaft ofthe pump drive system to a first end of its range, wherein thedriveshaft is in its distal-most position in which a distance between adistal end of the driveshaft and the cylinder is as small as possible;and engaging said second pumping cartridge retaining component with thesecond portion of the cartridge comprising a portion of the piston shaftof the pumping cartridge, so as to couple the piston shaft to thedriveshaft.
 9. A method for coupling a presterilized pumping cartridgeto a reusable pump drive assembly, the method comprising: positioning apiston assembly portion of the pumping cartridge in a first positionwithin the cylinder, the first position being proximal to an operatingregion of the cylinder in which a piston reciprocates during operation;sterilizing at least a cylinder assembly portion of the pumpingcartridge; inserting the cartridge sterilized in the sterilizing stepinto the pump drive assembly; engaging a first retaining component ofthe pump drive assembly with a first portion of the cartridge; andengaging a second retaining component of a driveshaft of the pump driveassembly with the piston assembly portion of the cartridge.
 10. Themethod of claim 9, further comprising before the sterilizing step, astep of sealing the pumping cartridge in sterilizable packaging.
 11. Themethod of claim 10, further comprising after the sterilizing step, astep of removing the cartridge from the sterilizable packaging.